Integration test with a Gaseous Detector and a Solenoidal Magnet for the Precise Neutron Lifetime Measurement
- Mr. Kodai YANO
- Mr. Kodai YANO (Kyushu University)
The neutron lifetime, τ=879.4±0.6 sec, is an important parameter for particle/nuclear physics and cosmology. There is, however an 8.6 sec(4.0σ) deviation between the measured values of the neutron lifetime using two methods. A new method with a Time Projection Chamber(TPC) is being implemented at BL05 MLF J-PARC using a pulsed cold neutron beam. A TPC records both the electrons from neutron beta decay and protons from the neutron-3He capture reactions in order to estimate the neutron flux. However, electron background signals require the largest correction and are source of uncertainly for this type experiment. It is confirmed by Monte Carlo simulation that an uniform magnetic field generated by solenoidal magnet along the neutron beam can greatly reduce this background. The detector has been constructed and the integration test with a magnet has been finished and we are now preparing for the operation with neutron beam. We will present the status of this experiment.